Rotary pump



3 Sheets-Sheet 1 ROTARY PUMP A. A. P. PETIT Dec. 22, 1964 Filed March 15. 1961 A. A. P. PETIT Dec. 22, 1964 ROTARY PUMP 3 Sheets-SheerI 2 Filed March l5. 1961 Dec. 22, 1964 A. A. P. PETIT 3,162,140

ROTARY PUMP Filed March l5. 1961 3 Sheets-SheetI 3 \\\Y\\\\\ 'al United States Patent O This invention relates to rotary pumps in general and has specific reference to methods of arranging a rotarydrive volumetric pump consisting of a fixed structure comprising a substantially cylindrical chamber having formed therein orifices lconstituting the suction and delivery ports for the uid, said chamber having arranged therein `an impeller consisting of a plurality or movable members driven from a shaft imparting thereto a movement of rotation or circular translation.

Hitherto known pumps of this general type are characterized by a fixed output for a given velocity of rotation, and actually the only way of varying this output is by varying their velocity of rotation.

On the other hand, the movable members or impeller elements housed within the cylindrical chamber, that is, according to the pump type contemplated, the gears, the eccentric piston, etc., must be fitted with a relatively high degree of precision not only in relation to the inner cylindrical wall of this chamber but .also in relation to the two lateral walls, so as to provide between the side faces of these movable members and these lateral walls a clearance sufiicient to avoid any jamming but small enough to avoid abnormal leakage losses. Therefore, the movable members and the casing of these pumps must be machined to very close tolerances and their assembly constitutes a delicate operation.

This invention provides a method of arranging pumps of the general type set forth hereinabove, whereby the above-listed inconveniences are eliminated, this method being remarkable notably in that it consists in permitting the movement of translation of at least one of the walls defining the lateral limits of said cylindrical chamber, to provide, if desired, a direct fiuid connection between said suction and delivery orifices, in order to vary the pump output at will.

Thus, the assembly method of this invention provides a volumetric pump wherein the output may be varied while maintaining its velocity of rotation to a constant value.

According to another feature of this invention, there is formed in the fiange, cover plate or like member secured on the pump casing a recess constituting somewhat the lateral extension of the aforesaid cylindrical chamber, on at least one of the sides thereof, and a movable plate is housed in this recess in the vicinity of said one side, this movable plate being adjustable in position and constituting the aforesaid movable wall.

According to a further feature characterizing this invention, there is created in said chamber an adjustable relative vacuum tending to move said movable plate away from the relevant side wall of the chamber with a view to vary the pump output as a function of the value of this relative vacuum.

From the foregoing it will be readily understood that the fact of submitting the position of the movable plate and therefore the pump output to a pressure makes it possible to render the pump operation considerably more flexible and therefore to widen the iield of its practical applications.

According to another characteristic feature of this invention resilient return means are provided for exerting -on said movable plate a predetermined pressure counter- ICC tending to press said movable plate against the side wall of said pump chamber.

lt will also be appreciated that with this construction it is possible not only to obtain an automatic play take-up action resulting from the provision of the aforesaid resilient return means but also and therefore to simplify considerably the lmachining and assembling of the component elements of the pump.

This invention is also concerned with rotary-drive volumetric pumps constructed according to the method broadly set forth hereinabove, that is, internal gear pumps, conventional gear pumps, swinging and guided vane rotary pumps, lobar pumps, eccentric pumps, etc.

Other features and advantages of this invention will appear as the following description proceeds with reference to the accompanying drawings illustrateddiagrammatically by way of example two typical forms of embodiment of the present invention. In the drawings:

FIGURE l is a diagrammatical cross section illustra-ting `a gear pump, the section being taken along the line I--I of FIGURE 2;

FIGURE 2 is an axial section taken upon the line Il-Il or FIGURE 1 and showing the improvements constituting the subject matter of this invention;

FIGURE 3 is an axial section showing a pump with an impel cylinder which is arranged in accordance with the teachings of this invention;

FIGURE 4 is a front View of the pump shown in FIG- URE 3, with the cover removed and the flange of the cylinder partly broken away;

FIGURE 5 is another axial section taken on line V-V of FIGURE 6 and illustrating a modied embodiment of the pump of FIGURE 3, and

FIGURE 6 is a section taken upon the line VI-VI of FGURE 5.

In the form of embodiment illustrated in FTGURES l and 2 of the drawings the pump consists essentially of a casing or body 1 comprising a substantially cylindrical internal chamber 2 and two orifices` or ports 3, Ai connected or adapted to be connected to the fluid intake and delivery pipes. Mounted within the cylindrical chamber 2 are the rotary members or impeller elements consisting 1n this example of two constantly meshing gears 5, 6 rotatably mounted about their shafts 7, 8, shaft 8 being operatively connected to the driving motor (not shown).

Secured on the two lateral faces of thecasing 1 are two anges 10 constitutingor receivingthe bearings of the gear shafts 7, 8. The inner face of flange 1@ is formed with a recess 1l constituting an extension, in the axial direction, of the aforesaidl cylindrical chamber 2. l-lousedin this recess lill is a movable plate l?, formed with a central orifice 13 fitting around an inner pin, boss, stud or like cylindrical projection 1d of flange 1t) which has its axis parallel to the axes of rotation of the gears. This movable plate i?. is slidably mounted on the inner pin ifi so that the latter acts both as a support and as a guide member. Of course, the movable plate 12 is also formed with bores 15, 16 necessary for the passage of the gear shafts 7, 8. This movable plate 12 is furthermore resiliently urged against the lateral face of casing 1 -by means of coil springs 17' or like means housed in cavities 18 of flange liti and bearing on said movable plate through the medium of domed heads 19 slidably fitted in these cavities.

A pipe 2t? provided with a valve 21 connects the recess 11 with the outside or with any closed spaced kept at a suitable device.

This pump operates as follows: When priming the pump, that is, before a substantially `pressure inferior to that of recess 1i, or with any other constant pressure is obtained in recess 1i, thesprings yor like resilient means 17 urge the movable plate 12 against FIGURE 3). l produces an oscillatory motion of the piston of which the the outer face of casing l, thus preventing any direct communication between the suction and delivery ports 3, 4 for the fluid. Under continuous operating conditions, a constant pressure is obtained in recess "al which tends to pre-ss also the movable plate l2 against the casing, this pressure depending on the induction and delivery pressure values or manometrical level.

When the valve Z1 is opened in order to connect the recess 11 with a space kept at a pressure lower than that prevailing in this recess 1i, a pressure reduction is observed in recess 1i and this pressure reduction causes the plate 12 to perform a movement of translation away from the casing on the pin le. Under these circumstances the suction and delivery ports are in dire-ct intercommunication through the recess il, thus determining a reduction in the pump output. f

Ot course, the springs are so calculated as to exert on the plate l2 a pressure of predetermined value which is a function, notably, o the desired output variation to be applied to the pump.

The space to which pipe Z@ is connected may be for instance a tank subjected to the atmospheric pressure. Pipe Ztl may also be connected to the suction side of the pump.

By modifying the position of the control member of valve 21 it is obvious that the-pump output `may be modilied at will.

Y perform oscillatory movements insidean annular cavity of the casing which is closed by said iiange and provided with a radial partition, the ports 28u, 2311 of the suction and delivery ducts of the pump opening on either side of said partition.

The pump comprises essentially ar casing 22 formed with a bore 23 and on which is mounted a xed body 24 having a cylindrical central portion 25 coaxial with-the bore 23. The cylindrical portion 25 and bore Storm together an annulm' cavity Ze provided at its upper portion with a xed radial partition 2.7 on either side of which open the ports 23a, lh of the suction and delivery ducts of the pump.

One of these ducts (the delivery duct or the suction duct, according to the direction of rotation of the pump) is shown` at 2S. The movable member or piston of the pump comprises a cylindrical portion 1?@ and a ilange 3@ extending at right angles to the axis of cylinder 2i?. The ange 3d? carries in its central portion a hollow hob 31 threaded'on a socket or sleeve 32 secured eccentrically on a shaft 33. A flexible blade .3d mounted between said socket and shaft maintains the eccentricity of the socket and piston assembly and resiiiently urges the cylinder Z9 against the wall of bore 23.

The cylinder is formed with a radial slot 23a for reserving the locationrot the fixed partition. The ange also carries, on its face opposite to that carrying the cylinder 29 and `substantially in front of the aforesaid radial slot; a roller 35 displaceable between the ltwo guide faces Voi the casing (only one of these faces Sdbeing visible in Y It is known that the rotation of shaft cylindrical portion 2 forms in the annular recess two chambers 2do, 26h, rmbeing the suction chamber and 26h thedelivery chamber when the pump rotates in the :direction indicated by F, and that it is ythe Variation in volume of these two chambers that produces the fluid Vsuction and delivery.

Secured on the front face 22a of casing?. is a cover 137 forming with the casing a .chamber ES adjacent to the as V39 located in recessessuch as di? of the cover 3"? and against the front face 22a by springs or Ylike means such f Vloaded studs or heads 39a slidably mounted in said recesses.

A pipe 4l pro-vided with a control valve d2 connects the chamber 38 with the outside. The cover 37 is so designed that the dimensions of chamber 38 are sufcient to permit a limited movement of translation of the piston and ltherefore of ilange 3d in a direction parallel to the axis of rotation of the pump. This chamber is of substantially cylindrical coniiguration and its diameter is substantially greater than that of flange Sti.

FGURES 5 and 6 illustrate a modified embodiment of the pump shown in FIGURES 3 and 4; this alternate embodiment is particularly adapted for installations distributing fluids in air-free circuits. lt is known in fact that in certain circuit arrangements the liquid output must be determined with a relatively high degree of precision, for example by means oi meters, and that therefore any air or gas circulation likely to alter the data given by these meters must strictlv be avoided.

ln FGURES 5 and 6 a tank i3 is mounted directly on the pump casing 22 so as to constitute therewith a unitary structure. The iiuid to be pumped iiows by gravity to the 4tank 4&3 through a pipe fitting 4d. The suction port 2S of the pump is connected to an intake pipe 5 opening substantially in the vicinity of the bottom of tank 43. The chief interest of this arrangement lies in the fact that air is prevented from penetrating into the circuit. This intake pipe d5 may also act as a baille and permits if desired a complementary extraction or any residual gas from lthe liquid. The delivery duct 2S is connected to another pipe litting do. The cham-ber 38 communicates with the tank d3 through a passage 47 provided at its end with a regulating device consisting for example of a double balanced valve it, 43' Vcontrolled by a iloat 49 connected through a rod Sil `to said valve. li desired, a cam or like device El controlled from the outside by means of a handle S2 and co-acting with a cam follower or like member 53 rigid with the rod Sil may be provided, whereby the float may be locked in a predetermined position to keep the valve in its open position. ln the pipe fitting d a spring-loaded Valve Slimay be mounted for closing the distributor circuit. The tank 43 is also provided with an orifice 55 for venting same to the atmosphere. The liquid contained in tank e3 is drawn by the pump up the intake pipe 45 and then forced through the pipe fitting 46 to the distributor circuit.

if the momentary quantity of liquid drawn by the purnp exceeds the liquid output fed to the tank 43 through the inlet iitting 4M, air will penetrate into the tank through the venting oriiicc 55. The iioat d@ will descend and thus open the double valveli, 43', thus creating a discharge and a :relative vacuum. in chamber 38. As a result, the piston will be displaced and the pump output reducedv accordingly. There is obtained automatically a condition of equilibrium whereby the pump output is adjusted exactly as a function of the iioat level in tank 'i.

lf the supply of liquid is discontinued, the tloat descends to a limit position whereat the pump output is reduced completely to zero. lt will be noted that the residual pressure under zero output conditions is considerably lower than the adjustment pressure of the spring-loaded or calibrated valve 5d. The output is stopped positively when the liquid level in the tank exceeds that of the inlet `Orifice of the intake pipe 45. Thus, the pump will never draw in air and therefore it cannot deliver air with the liquid.

Although the form of embodiment intended for avoiding pumping air through Ithe pump has been shown and described only with reference to an eccentric impeller pump, it will be noted that it is applicable directl to other types of rotary-driven volumetric pumps arranged according to the method of this invention.

'Of course, many modifications may be'brought to the device described herein, without departing from the spirit and scope of the invention,

Although the present method of construction of the invention has been illustrated in connection with external gear pumps and cylindrical impeller pumps, it will be readily understood by those conversant with the art that it is also applicable to internal gear pumps, Roote pumps, vane pumps, eccentric pumps, etc.

Of course, the present invention should not be construed as being limited to the few forms of embodiment illustrated and described herein as many modiications may be brought thereto without departing from the spirit and scope of the invention as set forth in the appended drawings.

What I claim is:

1. A volumetric pump with rotary drive comprising a casing which forms a cylindrical cavity, a radial xed partition in said cavity, a cover secured to said casing, said cover having internal blind hole means, a recess constituting an extension of said cavity and limited by said cover, a movable cylinder having a radial slot for receiving the location of said lined partition located in said cavi-ty, said cylinder dividing the latter into a suction and a delivery chambers, a suction port connected to said suction chamber, a delivery port connected to said delivery chamber, a power shaft, means eccentrically secured on said power shaft for imparting to said movable cylinder a movement or circularV translation combined with an osciliatory motion, a ilange formed solid with said movable cylinder and located in said recess, said flange constituting a separating wall between said cavity and said recess, the assembly comprising said ange and said movable cylinder being displaceable in translation parallel to the axis oi said power shaft to permit a direct interconnection between said suction and delivery chambers, springloaded studs slidably mounted in said blind hole means and projecting in said recess for resiliently urging said flange toward said cylindrical cavity, and duct means openingn in said recess to connect the latter to a space kept at a controlled pressure, said duct means comprising a control valve means for adjusting at will the pressure prevailing in said recess, the output of the volumetric pump being thus a function of the value of said pressure.

2. A pump as claimed in claim l comprising a tank fed with the liquid to be pumped, an intake pipe connected to said suction port and having an inlet orice opening near the bottom of Said tank and a duct connected to said recess and opening in said tank, said duct being provided with a regulating device responsive to the liquid level in said tank.

3. A pump as claimed in claim 1 wherein a locking member adapted to be actuated from the outside is provided for holding said regulating device in a predetermined ixed position.

4. A pump as claimed in claim l wherein said delivery port of said pump is connected to an outlet pipe provided with a non-return Valve urged to its open position by calibrated spring means, said Valve being adapted to close said outlet pipe before the liquid level in said tank attains the level of the inlet oriiice of said intake pipe.

5. A volumetric pump with rotary drive comprising a casing which forms a cylindrical cavity and a recess constituting an extension of said cavity, movable means in said casing, said movable means dividing said cylindrical cavity into a suction and delivery chambers, a suction port connected to said suction chamber, a delivery port connected to said delivery chamber, a power shaft to drive said movable means, a plate located in said recess said plate constituting a separating wall between said cavity and said recess, said plate being displaceable in translation parallel to the axis of said power shaft to permit a direct interconnection between said suction and said delivery chambem, calibrated return means located within said recess for resiliently urging said plate toward said cylindrical cavity, a tank fed with the liquid to be pumped, an intake pipe connected to said suction por-t and having an inlet orifice opening near the bottom of said tank, a duct connected to said recess and opening in said tank, said duct being provided with a regulating device responsive to the liquid level in said tank, an outlet pipe connected to said delivery port and provide-d with a nonretnrn valve urged to its open position by calibrated spring means, said valve being adapted to close said outlet pipe before the liquid level in said tank attains the level of the inlet oritice of said intake pipe.

References Cited by the Examiner UNITED STATES PATENTS 1,098,458 6/14 Nelson 16S- 131 1,497,050 7/24 Wardwell 230-141 1,694,805 12/28 Wiltse 103`42 1,780,109 10/30 Berglund 103-131 1,927,395 9/33 Edwards 103-126 2,134,153 10/38 Seyvertsen 103`42 2,210,152 8/40 Sacha 103-126 2,312,891 3/43 Ferris 10S-125 2,405,061 7/46 Shaw 103-126 2,437,791 3/48 Roth 103-l26 2,487,732 11/49 Schanzlin 103-126 2,642,001 6/53 Dale et al.

2,665,641 1/54 Lauck 103-126 2,769,394 11/56 Lauck 103-126 2,786,553 3/57 Boone et al. 103-126 2,793,595 5/57 Lauck 103-126 2,841,089 7/58 Jones 10S-131 2,845,868 8/58 Norlin 103-1-26 2,855,854 10/58 Aspelin 103-42 FOREIGN PATENTS 8,322 4/ 12 Great Britain.

LAURENCE V. EFNER, Primary Examiner. 

1. A VOLUMETRIC PUMP WITH ROTARY DRIVE COMPRISING A CASING WHICH FORMS A CYLINDRICAL CAVITY, A RADIAL FIXED PARTITION IN SAID CAVITY, A COVER SECURED TO SAID CASING, SAID COVER HAVING INTERNAL BLIND HOLE MEANS, A RECESS CONSTITUTING AN EXTENSION OF SAID CAVITY AND LIMITED BY SAID COVER, A MOVABLE CYLINDER HAVING A RADIAL SLOT FOR RECEIVING THE LOCATION OF SAID FIXED PARTITION LOCATED IN SAID CAVITY, SAID CYLINDER DIVIDING THE LATTER INTO A SUCTION AND A DELIVERY CHAMBERS, A SUCTION PORT CONNECTED TO SAID SUCTION CHAMBER, A DELIVERY PORT CONNECTED TO SAID DELIVERY CHAMBERR, A POWER SHAFT, MEANS ECCENTRICALLY SECURED ON SAID POWER SHAFT FOR IMPARTING TO SAID MOVABLE CYLINDER A MOVEMENT OF CIRCULAR TRANSLATION COMBINED WITH AN OSCILLATORY MOTION, A FLANGE FORMED SOLID WITH SAID MOVABLE CYLINDER AND LOCATED IN SAID RECESS, SAID FLANGE CONSTITUTING A SEPARATING WALL BETWEEN SAID CAVITY AND SAID RECESS, THE ASSEMBLY COMPRISING SAID FLANGE AND SAID MOVABLE CYLINDER BEING DISPLACEABLE IN TRANSLATION PARALLEL TO THE AXIS OF SAID POWER SHAFT TO PERMIT A DIRECT INTERCONNECTION BETWEEN SAID SUCTION AND DELIVERY CHAMBERS, SPRINGLOADED STUDS SLIDABLY MOUNTED IN SAID BLIND HOLE MEANS AND PROJECTING IN SAID RECESS FOR RESILIENTLY URGING SAID FLANGE TOWARD SAID CYLINDRICAL CAVITY, AND DUCT MEANS OPENING IN SAID RECESS TO CONNECT THE LATTER TO A SPACE KEPT AT A CONTROLLED PRESSURE, SAID DUCT MEANS COMPRISING A CONTROL VALVE MEANS FOR ADJUSTING AT WILL THE PRESSURE PREVAILING IN SAID RECESS, THE OUTPUT OF THE VOLUMETRIC PUMP BEING THUS A FUNCTION OF THE VALUE OF SAID PRESSURE. 